Layout Elements Combination Optimization of Variable Message Signs for Expressways in High-Density Road Network Areas

Abstract:

In order to determine the optimal layout elements combination of route guidance variable message signs （VMS） on the expressway in high-density road network areas， a PC-fixed driving simulator and an eye tracker were used to collect the behavior data of 20 participants under 4 VMS schemes and 2 normal traffic signs. An indicator variance analysis was conducted to test the differences among 6 different traffic signs including route guidance results， driving stability， driving load， and visual recognition behavior. The results suggest that there is no significant difference between VMS scheme 4 and normal traffic signs， which means that the driving safety can be ensured by this scheme. The index factor analysis method was applied to propose a parameter S that can comprehensively reflect the characteristics of various driving behavior indicators of drivers， and make the multiple quantitative evaluation of driving behavior. The results indicate that the performance of VMS scheme 4 is the optimal scheme. In summary， the layout elements combination of route guidance VMS for expressway in high-density road network areas is recommended as follows： the shape of the road network should be represented by topological diagrams， expressways should be represented by light strips connected horizontally and vertically， other roads should be represented by short horizontal lines， and the interchanges should be represented by circles. Red， yellow， and green colors should be used to respectively indicate congestion， slow traffic， and smooth traffic conditions. A white triangle should be used to identify the direction of interchange， the hub and general interchange should be respectively marked with the place name and the interchange name， and the driver’s current location should be highlighted.

Key words:transportation engineering;variable message signs (VMS);driving simulation;power spectrum analysis;visual behavior